The Wyrmling is currently pretty bad at following your character. He's also sometimes awful at defending himself, and loses pathing period. Just now he was trying to force himself through a wall while I was walking off. A mob came around the corner and started attacking him, he never even fought back.
Velz that seems to be the situation of all the pets from what I've heard and can confirm for mustache golem.
besides the obvious pathing issues I think the other big source of the problems with pets is that they don't "see" enemies an awful lot. My guess as to the problem is that just like mobs don't always see you based on your sneakiness, the pets have the same problem with the mobs. I think this because my pets worked relatively well on dwarvish moderation, but upon moving to going rogue it turned into a complete moron, sometimes going almost 10 turns before noticing an enemy.
